Distillation method

Abstract

The present application relates to a distillation device. The distillation device of the present application can minimize energy loss occurring in a purification process of the olefin monomer, the solvent, and the raw material including, for example, 1-octene, iso-octene, and n-hexane, used in a polymerization process of the polyolefin elastomer, and can increase economic efficiency by isolating a high-purity product.

The invention claimed is: 
     
       1. A distillation method, comprising:
 introducing a raw material comprising compounds represented by Formulas 1 and 2 below into a first supply port of a first distillation column, 
 obtaining a first top stream at an upper section of the first distillation column, and separately obtaining first, second and third bottom streams at a bottom section of the first distillation column,
 introducing the first bottom stream into a second supply port of a second distillation column, 
 obtaining a second top stream at an upper section of a second distillation column and obtaining fourth and fifth bottom streams at a bottom section of the second distillation column, 
 
 heat-exchanging the second top stream with the third bottom stream; and 
 isolating the compound represented by Formula 2 from the first top stream, and the compound represented by Formula 1 from the second top stream, 
 wherein Equations 1 and 2 below are satisfied: 
 
       
         
           
           
               
               
           
         
         wherein R 1  is a C 4  to C 12  alkyl group, and R 2  to R 4  are each independently hydrogen or a C 4  to C 12  alkyl group, 
         R 5  is a C 1  to C 4  alkyl group, and n is 1 to 4;
     T   t-2   −T   b-3 ≥8° C.,  [Equation 1]
 
     P   2   /P   1 ≥3.0,  [Equation 2]
 
 
         wherein T t-2  indicates a temperature of the second top stream, and T b-3  indicates a temperature of the third bottom stream, and 
       
       P 1  indicates a pressure of the upper section of the first distillation column in kg/cm 2  g, and P 2  indicates a pressure of the upper section of the second distillation column in kg/cm 2  g. 
     
     
       2. The method according to  claim 1 , wherein the compound represented by Formula 1 is at least one selected from the group consisting of 1-octene, iso-octene and a mixture thereof, and the compound represented by Formula 2 is n-hexane. 
     
     
       3. The method according to  claim 2 , wherein a content of n-hexane in the first top stream is 90% or more, and a content of 1-octene, iso-octene, or a mixture thereof in the second top stream is 90% or more. 
     
     
       4. The method according to  claim 1 , wherein the second top stream that is heat-exchanged with the third bottom stream is introduced into a second condenser, which is in fluid communication with the second distillation column, and a portion of the second top stream passing through the second condenser is introduced into the upper section of the second distillation column, and a remainder of the second top stream passing through the second condenser is introduced into a storage tank to store the compound represented by Formula 1 therein. 
     
     
       5. The method according to  claim 1 , wherein a pressure of the upper section of the first distillation column is 0.05 to 0.2 kg/cm 2  g. 
     
     
       6. The method according to  claim 1 , wherein a pressure of the upper section of the second distillation column is 1.0 to 2.0 kg/cm 2  g. 
     
     
       7. The method according to  claim 1 , wherein a temperature of the upper section of the first distillation column is 60 to 80° C. 
     
     
       8. The method according to  claim 1 , wherein a temperature of the lower section of the first distillation column is 120 to 145° C. 
     
     
       9. The method according to  claim 1 , wherein a temperature of the upper section of the second distillation column is 125 to 170° C. 
     
     
       10. The method according to  claim 1 , wherein a temperature of the lower section of the second distillation column is 130 to 180° C. 
     
     
       11. The method according to  claim 1 , wherein the compound represented by Formula 2 is a solvent used in polymerization of a polyolefin elastomer.